This change fixes an automated test related to disallowed fleet expenses after a Runbot failure. It helps keep the accounting and fleet expense checks reliable without changing day-to-day user functionality.

Runbot error build 163135

Date fields in Sign documents now show a placeholder that follows the company's configured language and regional date format. This prevents confusion for users preparing signature requests across different locations.

Before this commit, When adding a date sign item, the date format in the placeholder  might mismatch the company's location date format since it is a static value. After this commit, the placeholder value is dynamic, it is computed initially from the company lang date_format.

task-id: 4607440

A small naming issue was fixed in the Indian GST reporting workflow so the system can correctly recognize the field update behavior for tax units. This improves reliability and maintainability without changing the user-facing reporting process.

This **PR** rectifies the incorrect name on onchange method of tax_unit_id. This will help to improve the visibility of this method.